Aluminum nitride powder has been found to be an excellent filler material for thermally-conductive polymer composites used as heat sink materials in the electronics industry. Using aluminum nitride powder as a filler results in a polymer composite having higher thermal conductivity than when using the common filler, silica.
However, using virgin aluminum nitride powder in polymer composites is not without its problems. Polymer composites exhibit some water permeability, and, because aluminum nitride is sensitive to hydrolysis, some protection of the aluminum nitride powder from hydrolysis is desired.
A second problem with using virgin aluminum nitride powder occurs during storage of the powder. Air-borne moisture attacks the aluminum nitride powder causing the powder to experience an increase in oxygen content and a concomitant weight gain.
It is, therefore, a primary object of the invention to provide an easy method for making moisture-resistant aluminum nitride-containing powder.
It is another object of the invention to provide aluminum nitride-containing powder having a moisture-resistant protective layer on its surface.